A member of the Air Force's Wings of Blue Parachute Demonstration Team salutes as he jumps out of an aircraft, during the opening ceremony of Aviation Nation 2017 Nellis Air and Space Expo at Nellis Air Force Base, Nev., November 10, 2017. (Photo by Senior Airman Kevin Tanenbaum/Reuters/U.S. Air Force)

“The Dream Chaser is a planned crewed suborbital and orbital vertical-takeoff, horizontal-landing (VTHL) lifting-body spaceplane being developed by SpaceDev, a wholly owned subsidiary of Sierra Nevada Corporation (SNC). The Dream Chaser design is planned to carry seven people to and from low earth orbit. The vehicle would launch vertically on an Atlas V and land horizontally on conventional runways”. – Wikipedia

Photo: NASA Deputy Administrator Lori Garver talks during a press conference with Sierra Nevada's Dream Chaser spacecraft in the background at the University of Colorado at Boulder on February 5, 2011 in Boulder, Colorado. Sierra Nevada's Dream Chaser spacecraft is under development with support from NASA's Commercial Crew Development Program to provide crew transportation to and from low Earth orbit. NASA is helping private companies develop innovative technologies to ensure that the U.S. remains competitive in future space endeavors. (Photo by Bill Ingalls/NASA via Getty Images)

Antek Marciniec holds onto a slackline after falling off as he highlines between two cliffs at Diamond Bay on December 21, 2014 in Sydney, Australia. Slacklining is a balance sport in which participants walk on a flat nylon webbing anchored between two points with the tension adjusted to allow for slack, providing an experience similiar to that of walking on a trapmoline. Highlining is a style of slacklining where the two anchor points are set up with significant elevation from the ground or water. (Photo by Cameron Spencer/Getty Images)

A Typhoon jet flown by Flt Lt Jim Peterson practising over RAF Coningsby in the East Lindsey district of Lincolnshire, England on September 27, 2019 producing a rainbow effect over the plane. The rainbow is made of crystalized or frozen water vapor that reflect and refract sunlight, causing the rainbow effect. (Photo by Claire Hartley/Bav Media)

Fort Bourtange is a star fort located in the village of Bourtange, Groningen, Netherlands. It was built in 1593 under the orders of William the Silent. Its original purpose was to control the only road between Germany and the city of Groningen, which was controlled by the Spaniards during the time of the Eighty Years' War.

(L-R) Ozzy Osbourne and son, producer Jack Osbourne visit the Tribeca Film Festival 2011 portrait studio on April 25, 2011 in New York City. (Photo by Larry Busacca/Getty Images for Tribeca Film Festival)

Two men using an electric power saw to fell a tree circa 1940's. (Photo by Keystone View/FPG/Getty Images)

Two young women embrace in bed together, both wearing white lace underwear. (Photo by Popperfoto/Getty Images)